The present invention relates to a bending load beam, in particular for the bogie or truck frames of rail vehicles.
Rail vehicle truck or bogie frames of fiber sandwich construction are known (DE-PS No. 29 52 182), in which the longitudinal bending load beams connected by cross struts to each other, for carrying the wheeltrucks, in addition to the required carrying function, also assume the function of primary springs and must have a given strength and rigidity changing in the longitudinal direction and increasing from the relatively elastic longitudinal beam ends toward the beam center. Simultaneously, they must possess a high resistance to torsion.
Known fiber sandwich bending load beams, however, which in the manner of an I section with an upper and a lower flange with unidirectional fiber orientation and with a fiber composite load web placed between the flanges as a distance maintainer, have uniform bending strength and bending rigidity and a very low resistance to torsion. Such beams, furthermore, present the difficult problem of achieving sufficiently secure binding of the unidirectional reinforcement fibers with each other and with the load web, especially if high dynamic loads, localized in points, are introduced into the beam. Known are, furthermore, flexural springs of fiber composite, which consist either of a unidirectional fiber cord with fiber inserts embedded in it (DE-OS No. 31 19 856) or are formed multi-layered with an upper and a lower unidirectional flange and an interspaced fiber composite distance maintainino layer, provided with laterally projecting brackets for the application of load (DE-PS No. 32 38 099). Springs of this kind are, by their very nature, not suitable as bending resistant beams and have in comparison to the latter, relative to their bending and torsion resistance, great weight.